validatePositiveNumber

Validates a value as a positive number (greater than zero).

This helper never throws and never mutates input. Returns a structured ValidationResult for composable validation pipelines.

Signature

function validatePositiveNumber(
    value: unknown,
    field: string
): ValidationResult<number>

Parameters

Name	Type	Description
value	unknown	The value to validate.
field	string	The field name for error reporting.

Returns

• { ok: true; value: number }: If valid.
• { ok: false; field: string; message: string }: If invalid.

Examples

validatePositiveNumber(0.1, 'rate');      // → { ok: true, value: 0.1 }
validatePositiveNumber(42, 'count');      // → { ok: true, value: 42 }
validatePositiveNumber(-1, 'index');      // → { ok: false, field: 'index', message: 'Value must be a positive number' }
validatePositiveNumber(0, 'zero');        // → { ok: false, field: 'zero', message: 'Value must be a positive number' }
validatePositiveNumber("5", 'stringVal'); // → { ok: false, field: 'stringVal', message: 'Value must be a positive number' }

Notes

• Only number primitives greater than zero are valid.
• Fractional numbers are allowed.
• Zero, negative numbers, strings, NaN, Infinity, and non-numeric types fail.
• Use normalizePositiveNumber if input may be a string before validation.